Flighthub.com Rip-off of $1,600.00 when tying to use my flight credits. Cornwall Ontario

I have a $2,042.00 credit with flighthub due to a cancellation of 2 United Airlines tickets. Flight hub charged me a $300.00 cancellation fee at that time. Today I called United directly to find out what their going rate is for the same flight and destination as before. United’s price was $1,033.00 round trip for 2 tickets. When I called flight hub for the same flights etc. the price was my $2,042.00 credit plus another $290.00 per person, making the total $2,622.00. That’s nearly $1,600.00 more than what United wanted for the exact same tickets. I’ve tried to call but no one can explain the outrageous price difference or their supervisor just hangs up.